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Message-ID: <ZXL3L38i8RIFo+nh@nanopsycho>
Date: Fri, 8 Dec 2023 11:59:59 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: David Wei <dw@...idwei.uk>
Cc: Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCH net-next 1/3] netdevsim: allow two netdevsim ports to be
Thu, Dec 07, 2023 at 06:21:15PM CET, dw@...idwei.uk wrote:
>Add a debugfs file in
>/sys/kernel/debug/netdevsim/netdevsimN/ports/B/link
"peer" perhaps?
>
>Writing "M B" to this file will link port A of netdevsim N with port B of
>netdevsim M.
>
>Reading this file will return the linked netdevsim id and port, if any.
>
>Signed-off-by: David Wei <dw@...idwei.uk>
>---
> drivers/net/netdevsim/bus.c | 10 ++++
> drivers/net/netdevsim/dev.c | 97 +++++++++++++++++++++++++++++++
> drivers/net/netdevsim/netdev.c | 5 ++
> drivers/net/netdevsim/netdevsim.h | 3 +
> 4 files changed, 115 insertions(+)
>
>diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
>index bcbc1e19edde..3e4378e9dbee 100644
>--- a/drivers/net/netdevsim/bus.c
>+++ b/drivers/net/netdevsim/bus.c
>@@ -364,3 +364,13 @@ void nsim_bus_exit(void)
> driver_unregister(&nsim_driver);
> bus_unregister(&nsim_bus);
> }
>+
>+struct nsim_bus_dev *nsim_bus_dev_get(unsigned int id)
>+{
>+ struct nsim_bus_dev *nsim_bus_dev;
>+ list_for_each_entry(nsim_bus_dev, &nsim_bus_dev_list, list) {
>+ if (nsim_bus_dev->dev.id == id)
>+ return nsim_bus_dev;
>+ }
>+ return NULL;
>+}
>diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
>index b4d3b9cde8bd..72ad61f141a2 100644
>--- a/drivers/net/netdevsim/dev.c
>+++ b/drivers/net/netdevsim/dev.c
>@@ -25,6 +25,7 @@
> #include <linux/mutex.h>
> #include <linux/random.h>
> #include <linux/rtnetlink.h>
>+#include <linux/string.h>
> #include <linux/workqueue.h>
> #include <net/devlink.h>
> #include <net/ip.h>
>@@ -388,6 +389,99 @@ static const struct file_operations nsim_dev_rate_parent_fops = {
> .owner = THIS_MODULE,
> };
>
>+static ssize_t nsim_dev_link_read(struct file *file, char __user *data,
>+ size_t count, loff_t *ppos)
>+{
>+ struct nsim_dev_port *nsim_dev_port;
>+ struct netdevsim *peer;
>+ unsigned int id, port;
>+ char buf[11];
See below.
>+ ssize_t len;
>+
>+ nsim_dev_port = file->private_data;
>+ peer = nsim_dev_port->ns->peer;
>+ if (!peer) {
>+ len = scnprintf(buf, sizeof(buf), "\n");
>+ goto out;
>+ }
>+
>+ id = peer->nsim_bus_dev->dev.id;
>+ port = peer->nsim_dev_port->port_index;
>+ len = scnprintf(buf, sizeof(buf), "%u %u\n", id, port);
>+
>+out:
>+ return simple_read_from_buffer(data, count, ppos, buf, len);
>+}
>+
>+static ssize_t nsim_dev_link_write(struct file *file,
>+ const char __user *data,
>+ size_t count, loff_t *ppos)
>+{
>+ struct nsim_dev_port *nsim_dev_port, *peer_dev_port;
>+ struct nsim_bus_dev *peer_bus_dev;
>+ struct nsim_dev *peer_dev;
>+ unsigned int id, port;
>+ char *token, *cur;
>+ char buf[10];
# echo "889879797" >/sys/bus/netdevsim/new_device
# devlink dev
netdevsim/netdevsim889879797
I don't think that 10/11 is enough.
>+ ssize_t ret;
>+
>+ if (count >= sizeof(buf))
>+ return -ENOSPC;
>+
>+ ret = copy_from_user(buf, data, count);
>+ if (ret)
>+ return -EFAULT;
>+ buf[count] = '\0';
>+
>+ cur = buf;
>+ token = strsep(&cur, " ");
Why you implement this differently, comparing to new_device_store()?
Just use sscanf(), no?
>+ if (!token)
>+ return -EINVAL;
In general, in case of user putting in invalid input, please hint him
the correct format. Again, see new_device_store().
>+ ret = kstrtouint(token, 10, &id);
>+ if (ret)
>+ return ret;
>+
>+ token = strsep(&cur, " ");
>+ if (!token)
>+ return -EINVAL;
>+ ret = kstrtouint(token, 10, &port);
>+ if (ret)
>+ return ret;
>+
>+ /* too many args */
>+ if (strsep(&cur, " "))
>+ return -E2BIG;
>+
>+ /* cannot link to self */
>+ nsim_dev_port = file->private_data;
>+ if (nsim_dev_port->ns->nsim_bus_dev->dev.id == id)
Why not? Loopback between 2 ports of same device seems like completely
valid scenario.
>+ return -EINVAL;
>+
>+ /* invalid netdevsim id */
>+ peer_bus_dev = nsim_bus_dev_get(id);
>+ if (!peer_bus_dev)
>+ return -EINVAL;
>+
>+ peer_dev = dev_get_drvdata(&peer_bus_dev->dev);
>+ list_for_each_entry(peer_dev_port, &peer_dev->port_list, list) {
>+ if (peer_dev_port->port_index == port) {
>+ nsim_dev_port->ns->peer = peer_dev_port->ns;
>+ peer_dev_port->ns->peer = nsim_dev_port->ns;
>+ return count;
>+ }
>+ }
>+
>+ return -EINVAL;
>+}
>+
>+static const struct file_operations nsim_dev_link_fops = {
>+ .open = simple_open,
>+ .read = nsim_dev_link_read,
>+ .write = nsim_dev_link_write,
>+ .llseek = generic_file_llseek,
>+ .owner = THIS_MODULE,
>+};
>+
> static int nsim_dev_port_debugfs_init(struct nsim_dev *nsim_dev,
> struct nsim_dev_port *nsim_dev_port)
> {
>@@ -418,6 +512,9 @@ static int nsim_dev_port_debugfs_init(struct nsim_dev *nsim_dev,
> }
> debugfs_create_symlink("dev", nsim_dev_port->ddir, dev_link_name);
>
>+ debugfs_create_file("link", 0600, nsim_dev_port->ddir,
>+ nsim_dev_port, &nsim_dev_link_fops);
>+
> return 0;
> }
>
>diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
>index aecaf5f44374..1abdcd470f21 100644
>--- a/drivers/net/netdevsim/netdev.c
>+++ b/drivers/net/netdevsim/netdev.c
>@@ -388,6 +388,7 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
> ns->nsim_dev = nsim_dev;
> ns->nsim_dev_port = nsim_dev_port;
> ns->nsim_bus_dev = nsim_dev->nsim_bus_dev;
>+ ns->peer = NULL;
> SET_NETDEV_DEV(dev, &ns->nsim_bus_dev->dev);
> SET_NETDEV_DEVLINK_PORT(dev, &nsim_dev_port->devlink_port);
> nsim_ethtool_init(ns);
>@@ -409,6 +410,10 @@ void nsim_destroy(struct netdevsim *ns)
> struct net_device *dev = ns->netdev;
>
> rtnl_lock();
>+ if (ns->peer) {
>+ ns->peer->peer = NULL;
>+ ns->peer = NULL;
What is this good for?
>+ }
> unregister_netdevice(dev);
> if (nsim_dev_port_is_pf(ns->nsim_dev_port)) {
> nsim_macsec_teardown(ns);
>diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
>index 028c825b86db..ac7b34a83585 100644
>--- a/drivers/net/netdevsim/netdevsim.h
>+++ b/drivers/net/netdevsim/netdevsim.h
>@@ -125,6 +125,7 @@ struct netdevsim {
> } udp_ports;
>
> struct nsim_ethtool ethtool;
>+ struct netdevsim *peer;
> };
>
> struct netdevsim *
>@@ -417,3 +418,5 @@ struct nsim_bus_dev {
>
> int nsim_bus_init(void);
> void nsim_bus_exit(void);
>+
>+struct nsim_bus_dev *nsim_bus_dev_get(unsigned int id);
>--
>2.39.3
>
>
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